Electric shavers usually have one or more cutter elements driven by an electric drive unit in an oscillating manner where the cutter elements reciprocate under a shear foil, wherein such cutter elements or undercutters may have an elongated shape and may reciprocate along their longitudinal axis. Other types of electric shavers use rotatory cutter elements which may be driven in an oscillating or a continuous manner. Said electric drive unit may include an electric motor or a magnetic-type linear motor, wherein the drive unit may include a drive train having elements such as an elongated drive transmitter for transmitting the driving motion of the motor to the cutter element, wherein said motor may be received within the handle portion of the shaver or in the alternative, in the shaver head thereof.
Irrespective of the architecture of the drive unit and the drive train, the cutter elements, in addition to the aforementioned cutting motion, may be movable in other directions so as to self-adapt to the contour of the skin to be shaved. For example, the cutter elements may be part of a shaver head that is slewable about one or more axes relative to the handle of the shaver, wherein the support structure connecting the shaver head to the handle may allow the shaver head to swivel about a swivel axis extending substantially parallel to the elongated cutter elements and/or the reciprocating axis thereof. In addition or in the alternative, the supporting structure may allow the shaver head to tilt about a tilting axis extending transverse to the longitudinal axis of the handle and transverse to the elongated cutter elements and/or the reciprocating axis thereof. In addition to or in the alternative to such shaver head movements, the cutter elements may dive into the shaver head and/or the shaver head may dive towards the handle so as to adjust the position relative to the skin contour to be shaved.
The support structure connecting the shaver head to the handle may have different configurations so as to allow for the aforementioned swiveling and/or tilting movements and to avoid collisions with the drive train extending from the drive unit to the cutter element. For example, the support structure may include a so-called four-joint linkage formed by a pair of link arms which are, on the one hand, pivotably mounted to the handle and, on the other hand, pivotably mounted to a shaver head part such as a shaver head frame, wherein the pivotable joints connecting the link arms to the handle and the shaver head, respectively, may define pivot axes parallel to each other and parallel to the tilting or swiveling axis defined by such four-joint linkage. Due to slewing or rotating movements of the link arms, the shaver head may tilt or swivel to adjust its rotatory position to better follow the skin contour.
Such support structures are sometimes rather difficult to be cleaned. Hair dust or hair stubbles from the cutter elements may get stuck on the support structure and neighboring surfaces and may form a cake or deposits in corners and recesses what may impair the movability of the shaver head.
For example, prior art reference US 2010/0175264 A1 shows such four-joint linkage of the shaver head to the handle, wherein the link arms are arranged in a sort of pendulum or hanging arrangement. An interposer part attached to the handle includes two poles projecting upwards into the shaver head, wherein the link arms are pivotably attached to the top end portions of such poles to extend or hang downwards back towards to the handle. The lower end portions of such hanging link arms are pivotably connected to a shaver head frame.
A similar support structure movably connecting the shaver head of an electric shaver to the handle thereof is shown by reference JP 2016-77464 A also showing a four-joint linkage including a pair of hanging link arms.
Another support structure allowing for swiveling and tilting of the shaver head of an electric shaver about swiveling and tilting axes is shown by EP 2 435 218 B1 suggesting a cardanic support structure including a shaver head frame pivotably mounted to a cradle-like handle part and, on the other hand, pivotably supporting a cutter frame on which the cutter element is supported.
Document US 2008/0034591 A1 discloses an electric shaver with reciprocating cutter elements in the shaver head, wherein said shaver head can be pivoted relative to the handle into various directions by means of a ball joint arranged between the handle and the shaver head. The action of the motor received in the handle is transferred to the cutter element in the head by means of a spring.
Document EP 1547735 A1 shows a shaver with a shaver head pivotably connected to the handle via a four-joint linkage. More particularly, a central support post projects from the topside of the handle into the shaver head, wherein a pair of linkage arms connecting the shaver head to the central support post are accommodated within the shaver head.
Furthermore, AT 409604 B shows an electric shaver having cutter elements which may, in addition to the oscillating cutting movements, pivot about an axis perpendicular to the shaver's longitudinal axis and the axis of oscillation of the cutter element so as to allow for adjustment of the cutter element position to the skin to be shaved, and rotatorily oscillate about an axis parallel to the longitudinal axis of the shaver housing. The transmission train connecting the drive motor to the cutter elements includes a coupling structure rotatorily oscillating about a pivot axis parallel to the shaver housing's longitudinal axis.
US 2009/0025229 A1 discloses a drive unit for the cutter elements of an electric shaver, wherein the drive unit includes transmitter pins extending from the shaver housing towards the shaver head, wherein the oscillating driving movements of said transmitter pins are applied onto the cutter elements via an oscillatory bridge supported for oscillatory reciprocation in the shaver head, wherein said oscillatory bridge includes yielding coupling arms so as to allow for adjusting movements of the cutter elements. A similar transmission architecture is known from U.S. Pat. No. 7,841,090 B2.
Further electric shavers allowing for adapting movements of the cutter elements are known from EP 1886775 A1, DE 20 2015 103 618 U1, EP 1935585 A1, DE 10 2008 031 132 A1, US 2004/231160 A1, U.S. Pat. No. 3,748,371 B, FR 1391957 A, GB 811,207 B and U.S. Pat. No. 5,704,126 B.